Phenolic resins are synthetic materials that vary greatly in molecular structure. This variety allows for a multitude of applications for these resins. One example of a phenolic resin is polycyclopentadiene diphenol, which is discussed in U.S. Pat. Nos. 3,419,624 and 4,546,129. Polycyclopentadiene diphenol may be used as a curing agent and/or to prepare the corresponding epoxy, cyanate and/or allyl thermosettable resin. These curing agents and/or resins can provide enhanced physical and/or mechanical properties to a cured composition due to the presence of the dicyclopentadienyl moiety and/or the functional group (e.g., the diphenol moiety). For example, cured compositions formed from such resins can have both a high glass transition temperature (Tg) and a relatively low water uptake.
To achieve these properties, however, would require the resin to have a high functionality (i.e., chemical groups available for crosslinking). As the functionality increases in these resins, so does their molecular weight. As the molecular weight increases, so does the melt viscosity of the resin. Having a high melt viscosity can lead to difficulties in using such resins.